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<br />9.84 ids) on two instrumented pipelines. <br />~j ~ <br />..- <br />Analysis found low pipe responses, swains, and calculated stresses fmm even large blasts. <br />Ground vibrarioa of 120 to 250 rands (4.72 !0 9.84 ids) produced worst case swains that <br />were about 25% of the swains resulting from normal pipeline operations and calculated <br />stresses of only about ]0•i6 to l8% of ffie ultimate teagile strength. No psesgurizatian <br />failures or permanent strains owurred even at vibration amplitudes of 600 mm/s (23.62 <br />ids)... <br />...Although particle velocities of over 600 mm/s (23.62 ids) wen sustained without loss <br />of pipe integrity, it is recommended that 125 mm/s (4.92 ids) measured at the surface is <br />a safe-level criterion for large surface mine blasts for Glade B or better steel pipelines. <br />The same criterion is recommended fir SDR 26 or better PVC pipe...Also, no adjustment <br />is believed needed for pipeline age. assuming the protective coating is intact, unless the <br />pipeline is ]mown to be at higher risk from previous damage or other causes. The same <br />safe-level criterion also appears applicable, at a minimum, w vertical wreUs and <br />telephone litu;s.~ <br />The primary blasting risk to pipelines appears to be from block motion or from having the <br />Pipeline is the scdtal ixater zone. In both cages, permanent strain has occurred in the <br />surrounding geologic ma6erisl, which is weaker than the pipe. <br />In the early 1960's work was tmdertakea by the American Gas Association Pipeline Research <br />Committee to establish limit for charge sin (pounds per delay) and distance from a bLut to <br />high-pressure gas transmission pipelines. The primary research found that there had been no <br />reported cage of pipeline failure due to normal blasting activities. Only when explosives were <br />detonated directly adjacent to a pdpe.line, were failures recorded. <br />~ Ibid., pp. 1,36. <br />• <br />